OK so the printers definitely need my book in pdf/x-1 format which means I get multiple errors coming up when I do the preflight check in that profile.

The Word tables which I converted to vector files come up with dozens of "Polygon### Object colourspace is not CMYK or spot".I didn't know that vector files could even be RGB or CMYK, it seemed a pretty good workaround to get tables in Scribus.

Can't see a way of changing the vector files, not the way I was creating them, anyway (postscript virtual printer).

If you export as a bitmap with sufficient resolution it should work well enough for most documents but, in your case, it sounds like you will need to be able to export with a CMYK colourspace/profile which might be difficult - or maybe not, I have never tried.

Affinity Designer allows you to export slices as "SVG (for print)" - amongst many other things - but I've never used that particular function so I don't know how well it works.

And then there's always the possibility of using LaTeX in a render frame.

That doesn't seem to be a particularly complicated table so I'm sure there will be lots of ways of getting what you want.

Can you try the thing mentioned in the linked article? Specifically, go into Colours and edit each colour, setting it to be CMYK instead of RGB. Does that do what you need? (Best to see if the simple stuff works before trying other things.)

Imported a table which had coloured cells using the vector files I had done by virtual printer; edit>colours and fills; edited all the RGB colours to their suggested CMYK equivalents; table displays correct colours (no out of gamut highlighting now) and no preflight errors under x-1a or x-3

Could be something for the Wiki, thanks for bouncing the ideas around Garry